Closed Bug 493958 Opened 16 years ago Closed 16 years ago

a/v sync problems when seeking

Categories

(Core :: Audio/Video, defect)

x86
macOS
defect
Not set
normal

Tracking

()

VERIFIED FIXED

People

(Reporter: blizzard, Assigned: cpearce)

References

()

Details

(Keywords: verified1.9.1)

Attachments

(2 files, 2 obsolete files)

On trunk when seeking in a big file I see A/V sync problems when the video plays after the seek. It's something persistent, too, doesn't fix itself when you pause and restart. Use the URL above and seek around a bit - 20 minutes in, 30 minutes in, jump back and forth and it will eventually get out of sync. This is on OSX, Minefield source build from this morning.
Flags: blocking1.9.1?
I think this may have something to do with bug 463358. The audio time isn't matching up to the seeked frame times.
I agree with Blizzard that this blocks. Seeking in a video is a common action. We should support it in ways that don't affect sync. I know bug 463358 hadn't blocked, but here we are.
Flags: blocking1.9.1? → blocking1.9.1+
fwiw after seeing how much of a huge difference using keyframes makes in the seeking experience I think we should block on bug 463358 as well. It's like night and day - no foolin'.
Attached patch Patch v1 (obsolete) (deleted) — Splinter Review
* If Ogg gives us extra audio data in the frames we skip after the seek (to account for latency...), include the same amount in the first frame after seek.
Attachment #378787 - Flags: superreview?(roc)
Attachment #378787 - Flags: review?(chris.double)
Comment on attachment 378787 [details] [diff] [review] Patch v1 >+ if (frame) >+ delete frame; Don't need null check for delete. > frame = NextFrame(); >+ audioData.AppendElements(frame->mAudioData); >+ audioTime += frame->mAudioData.Length() / >+ (float)mAudioRate / (float)mAudioChannels; frame can be NULL after the NextFrame call. >+ size_t numExtraBytes = mAudioChannels * mAudioRate * audioTime; >+ // numExtraBytes must be evenly divisble by number of channels. >+ while (numExtraBytes % mAudioChannels) >+ ++numExtraBytes; numExtraBytes should be numExtraSamples? They're floats, not bytes.
size_t count = mAudioChannels * mAudioRate * mCallbackPeriod; + // count must be evenly divisble by number of channels. + while (count % mAudioChannels) + ++count; Eeek! Please, count = mAudioChannels * PRInt32(NS_ceil(mAudioRate*mCallbackPeriod)) + // liboggplay gave us more data than expected, we need to prepend + // extra data to current frame keep audio in sync. This comment is a bit confusing. How about // Some of the audio data from previous frames actually belongs to this frame // and later frames. So rescue that data and stuff it into the first frame. + size_t numExtraBytes = mAudioChannels * mAudioRate * audioTime; mAudioChannels*PRInt32(NS_ceil(mAudioRate*audioTime)) + memcpy(dst, data, numExtraBytes); Wrong copy size
Attached patch Patch v2 (obsolete) (deleted) — Splinter Review
With review comments addressed.
Attachment #378787 - Attachment is obsolete: true
Attachment #378795 - Flags: superreview?(roc)
Attachment #378795 - Flags: review?(chris.double)
Attachment #378787 - Flags: superreview?(roc)
Attachment #378787 - Flags: review?(chris.double)
Attached file test for seeking to end (deleted) —
Download this file: http://tinyvid.tv/file/2g4f61jmrrz06.ogg Put the file in a local directory along with the attached .html file. Load the page in the browser, click 'end'. The assertion about there being no frame will fire.
Attachment #378795 - Flags: review?(chris.double) → review+
Attached patch Patch v3 (deleted) — Splinter Review
My update to avoid throwing away the last frame.
Attachment #378795 - Attachment is obsolete: true
Attachment #378795 - Flags: superreview?(roc)
With this patch I sometimes see us failing to seek to a keyframe initially so we get I-frame garbage, but I don't think it's a regression in this patch. Must be a bug in the seek-to-keyframe logic. I'll file a new bug for that.
Attachment #378802 - Flags: review?(chris.double) → review+
I made a https://bugzilla.mozilla.org/show_bug.cgi?id=466699#c24 that this is still broken for me. Perhaps i should move the issue over here?
(In reply to comment #12) > I made a https://bugzilla.mozilla.org/show_bug.cgi?id=466699#c24 that this is > still broken for me. Perhaps i should move the issue over here? Filed Bug 495004 for this. Thanks for spotting this Tony.
Verified fix on Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1pre) Gecko/20090526 Shiretoko/3.5pre Ubiquity/0.1.5 and Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.2a1pre) Gecko/20090526 Minefield/3.6a1pre
Status: RESOLVED → VERIFIED
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